[shad9876]

[IMG][/IMG]

I painted my '56 Chevy about 2 years ago. Deployed for a year and when I got back I have a couple of areas with little bumps. I probably rushed the coats. The bubbles do not feel squishy or hollow. I did all the body and paint work myself (took it down to bare metal) and am sure it is not a rust issue.

Unfortunately, I think they are raised just a little too high to be able to sand flat and still have clear to polish, but I'm tempted to try. If I'm gonna have to sand it down and repaint it, I might as well try it first.

Any other suggestions on repair options without re-basing and re-clearing the entire panel??

[69 widetrack]

It may not be rust, but left alone it probably will be...bubbles or blisters in paint are usually caused by moisture...this moisture very often comes out of your compressor into your air line and out your gun...You may not see it when you paint and it can take years for it to show up as a blister or bubble. The only solution is, as you said to sand it down, polishing is not and option, it needs to be removed, repaired, and painted.

Sorry about that but that's what it looks like and usually it is.

Ray

[69 widetrack]

As far as repairs go, you can remove the blister by block sanding, priming the area with appropriate primers, block sand, blend the base coat and re-clear the panel...you could spot paint it and polish, but that brings other issues to the table...This method is probably the safest with the best results. When re-doing the panel, make sure your compressor isn't spitting out moisture but using filters and moisture traps for insurance.

Ray

[JoAnnBortles]

Originally Posted by 69 widetrack

It may not be rust, but left alone it probably will be...bubbles or blisters in paint are usually caused by moisture...this moisture very often comes out of your compressor into your air line and out your gun...You may not see it when you paint and it can take years for it to show up as a blister or bubble. The only solution is, as you said to sand it down, polishing is not and option, it needs to be removed, repaired, and painted.

Sorry about that but that's what it looks like and usually it is.

Ray

I have to agree with Ray. But there is no telling exactly what it is until you cut into one of the bubbles. I know you do not want to do that. But something is going on.
As for rust, metal is very porous, and sometimes rust can be deep in the metal, you grind and clean off the surface. It looks good and clean but underneath that rust is there and it will travel up to the surface once again. I know cos I went through this when I restored my 66 Pontiac Bonneville. 2 years later the rust returned and I was so sure I got it all.
So I have been exactly where you are. Gorgeous paint on my car and as it was a candy, there was really no way to spot repair it.
If you want to know exactly what's going on, you're going to have to dig into one of the bubbles. You can try sanding it down. Use a hard block like one of Motor Guards Run Blockers. I use these all the time in cases where I have to sand something out and not get to too far into the surrounding clear. Maybe you'll be lucky and they sand out.
Good Luck. Hope its not rust but I think it just might be.

[69 widetrack]

Originally Posted by JoAnnBortles

I have to agree with Ray. But there is no telling exactly what it is until you cut into one of the bubbles. I know you do not want to do that. But something is going on.
As for rust, metal is very porous, and sometimes rust can be deep in the metal, you grind and clean off the surface. It looks good and clean but underneath that rust is there and it will travel up to the surface once again. I know cos I went through this when I restored my 66 Pontiac Bonneville. 2 years later the rust returned and I was so sure I got it all.
So I have been exactly where you are. Gorgeous paint on my car and as it was a candy, there was really no way to spot repair it.
If you want to know exactly what's going on, you're going to have to dig into one of the bubbles. You can try sanding it down. Use a hard block like one of Motor Guards Run Blockers. I use these all the time in cases where I have to sand something out and not get to too far into the surrounding clear. Maybe you'll be lucky and they sand out.
Good Luck. Hope its not rust but I think it just might be.

Good call JoAnn, and thank you for adding, you are so right...it may not even be trapped moisture, it could be a rust spot from underneath and created a "pin hole" or as you said it may have been on the surface of the outer metal the whole time. If a person has been in the trade long enough and done enough vehicles, they know this is not an uncommon problem on vehicles especially older vehicles.

Usually in cases like this, moisture is the culprit that caused the metal to oxidize under the paint...when metal oxidizes it gives off gasses, these gasses cause expansion and they result in bubbles in your paint.

JoAnn, good to hear from you again, I think it's been awhile since I saw you last post.

Ray

[sunsetdart]

Here's a very important tip to anyone doing painting in their shop............
Please take the time to drain your compressor. It should be drained at least once a month. If not to remove moisture from your airlines, but keep the inside of the tank from corroding as well.
Having a good filter right inline is always a good thing.

[Old Fool]

Originally Posted by shad9876

[IMG][/IMG]

I painted my '56 Chevy about 2 years ago. Deployed for a year and when I got back I have a couple of areas with little bumps. I probably rushed the coats. The bubbles do not feel squishy or hollow. I did all the body and paint work myself (took it down to bare metal) and am sure it is not a rust issue.

Unfortunately, I think they are raised just a little too high to be able to sand flat and still have clear to polish, but I'm tempted to try. If I'm gonna have to sand it down and repaint it, I might as well try it first.

Any other suggestions on repair options without re-basing and re-clearing the entire panel??

Please give full details about the panel from start to finish, ie, sand blast? soda? phospo, acid wash, sanding?
Thanks.

[johnnyg]

It is moisture or rust raising the paint off the metal.

[35prog]

Hello, Appears the majority feel it is moisture related, I believe it may be just a "gassing out" issue. If there is any filler in that area it may be that a pinhole in the filler was bridged and an air pocket was the result. Did you use etch primer or epoxy on the bare steel?

[ReflectImage]

That's a terrible feeling when something like this happens; I've been there! Like the other replies if your going to get help you need to tell what products & what procedure you used. From experience and advise from PPG that we received - you need to 'seal' before laying down the the color. This could be what happened if didn't you seal the primer surfacer before painting. It could be that the color was so hot (chemically) that it burned right into your surfacers and body filler and then trapped moisture under the surface. If you haven't solved the problem yet, as I see it the only way is to find out. Would be to first lay down a strip of masking tape on all four side of the bubble and shave it off with a razor blade. Then let the viewers know 1)what you see, 2) what products you use maybe then someone can give you hand in where to go next. Just so you know I am not current on todays 2 stage products, only experience is with one stage and sealing with with DP-40 before paint.

[69 widetrack]

[QUOTE=ReflectImage;1630742]That's a terrible feeling when something like this happens; I've been there! Like the other replies if your going to get help you need to tell what products & what procedure you used. From experience and advise from PPG that we received - you need to 'seal' before laying down the the color. This could be what happened if didn't you seal the primer surfacer before painting. It could be that the color was so hot (chemically) that it burned right into your surfacers and body filler and then trapped moisture under the surface. If you haven't solved the problem yet, as I see it the only way is to find out. Would be to first lay down a strip of masking tape on all four side of the bubble and shave it off with a razor blade. Then let the viewers know 1)what you see, 2) what products you use maybe then someone can give you hand in where to go next. Just so you know I am not current on todays 2 stage products, only experience is with one stage and sealing with with DP-40 before paint.[/QUOT

I wasn't going to reply but after thinking it over I decided I better and the only reason is that if someone else reads this they are not getting the right information.

ReflectImage....I don't mean to offend you but in this case you are wrong...If this is the information that a PPG rep gave you...The PPG rep was wrong. Sealer has absolutely nothing to do with what happened here, sealer is a product designed to even out poor substrates, for example, if you have a vehicle with several different substrates, say lacquer primer and or whatever Acrylic Enamel, or a vehicle that is not sanded with the fine grit required so sand scratches won't show when painted. If a vehicle is prepped properly and the substrate (either existing paint or a quality primer) is consistent, sealer is not required and has no bearing on what happened here.

The problem is either trapped moisture under the paint causing rust or existing rust that was not removed completely before painting.

So again ReflectImage, I'm not trying to offend, I'm just trying to correct...And yes, I was a Rep for PPG.

Ray

[deadbodyman]

It could even be a lacquer primer if that was used... we need to know if it was stripped to the metal and what was done after that metal preps ,primers did you wax & grease it...theres a ton of stuff but moisture\oil in the air line and lacquer primers or improper metal prep are the most common.but explain the proceedure and materials used from start to finish. but be prepared ,when you see bubbles even small ones theres only two ways to deal with it ,,,,live with it or sand down untill the bubbles are gone,most times it has to go all the way to the metal before they're gone..but you might get lucky and only the paint has to come off...never know but you cant just buff them out ,you need to fix the problem or just deal with it..
.It looks pretty good from here though

[Old Fool]

Originally Posted by deadbodyman

It could even be a lacquer primer if that was used... we need to know if it was stripped to the metal and what was done after that metal preps ,primers did you wax & grease it...theres a ton of stuff but moisture\oil in the air line and lacquer primers or improper metal prep are the most common.but explain the proceedure and materials used from start to finish. but be prepared ,when you see bubbles even small ones theres only two ways to deal with it ,,,,live with it or sand down untill the bubbles are gone,most times it has to go all the way to the metal before they're gone..but you might get lucky and only the paint has to come off...never know but you cant just buff them out ,you need to fix the problem or just deal with it..
.It looks pretty good from here though

Apparently the OP does not want to tell how he prepped and painted the car to figure the problem out.

Doesn't look like he even returned to the post?

He could shave the surface off and see what is under there, a careful shave cut and one of those fake bullet hole stickers and he would be set <jk>

My hunch is acid wash primer or similar as the original cause. But I am not a gambling man, so I wouldn't put any money on my hunch,LOL.

[69 widetrack]

Originally Posted by deadbodyman

It could even be a lacquer primer if that was used... we need to know if it was stripped to the metal and what was done after that metal preps ,primers did you wax & grease it...theres a ton of stuff but moisture\oil in the air line and lacquer primers or improper metal prep are the most common.but explain the proceedure and materials used from start to finish. but be prepared ,when you see bubbles even small ones theres only two ways to deal with it ,,,,live with it or sand down untill the bubbles are gone,most times it has to go all the way to the metal before they're gone..but you might get lucky and only the paint has to come off...never know but you cant just buff them out ,you need to fix the problem or just deal with it..
.It looks pretty good from here though

I could see lacquer primer being the culprit because it's porous and sucks up moisture like a sponge and if there isn't any etch or epoxy underneath it could start to rust. I've never seen oil cause this kind of a reaction 1 year after it's painted though, usually oil contamination is visible right away...the only way I could see oil cause this is if it was painted in cool weather and when it warmed up it expanded and made the paint let go from the metal. The car does look like it was cut and buffed so we don't know if he had a massive fish eye in those spots...if he did have fish eyes in those spots and they where cut and buffed and painted when cool, then I could possibly see oil as an issue. Well unless the OP gives us this information, like mentioned, the OP needs to give us that information.

Ray

[ReflectImage]

Hello 69 Widetrack. No worry, I am too old to be offended and I am always ready to learn. Anyway you are most lightly right about this particular situation of small paint bubbles/blisters. With my situation, the deck lid brook out in little raised bubbles after sitting in the sun for a few hours. The Deck lid was chemically stripped down & dried before applying DP40 metal sealer, followed with body fillers and primers. I am sure we were using Ditzlers Polyurethane Black Paint, being black may have something to do with it. The mistake we made according to the rep (I want make a correction it was a Ditzler rep) he said we were supposed seal with DP40 before laying down the paint, to keep the paint from burning into the substrates. We took the deck lid down to metal & redid the body work, got it all in the same substrate and followed the rep suggestions, spayed on a light reduced coat of DP40, scuffed lightly with scotchbrite before laying down the paint. Wrong or right - it turned out great. To make a long story short - we continued to do other cars with the same process. This was a long time ago - have been retired for over ten years - I guess things have changed. Anyway, what happened to this thread starter?